1. Field of Invention
The present invention relates to a fuel injection amount compensating method of precisely compensating an amount of fuel injected by an injector to reduce vibration and noise mainly generated by a combustion process.
2. Description of Related Art
In generation, it is known that a diesel engine has larger vibration and noise than a gasoline vehicle. In order to reduce the vibration/noise, pilot injection is introduced.
In the pilot injection, before an injector performs main injection for combustion, a predetermined amount of fuel is previously injected at a predetermined point in time so that temperature of a combustion chamber is raised and a mixture of fuel and air is improved. The pilot injection is performed at least once and may be multiply performed in accordance with a driving condition.
Through the pilot injection, ignition delay is reduced and a rate of rise of combustion pressure is reduced. As the rate of rise of the combustion pressure is reduced, combustion noise is reduced.
On the other hand, as an operation period of an injector that injects fuel is increased, a pilot injection amount is reduced or increased by various causes. In general, the pilot injection amount is reduced.
As the pilot injection amount is reduced, the rate of rise of the combustion pressure of the combustion chamber is increased and vibration and noise are increased.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.